Well, since I've been semi-successfully (very unsuccessfully at the beginning) trying to learn to fly a plane in this simulator, I thought it might be useful to list a few things I've learned that seem to be very easy beginner mistakes to do that tend to end with death.
I haven't started messing with prop pitch or any other pitch, or complex engine management, but otherwise I'm playing realistically as possible, so here are a few things.
1) Flaps are very, very important. Make sure they're in the right position depending on what you're doing. Landing, take off, combat, raised, learn what they are good for.
2) Make sure you learn to use the RUDDER when taking off or you will careen into a nearby tree. It's the only way you can manuever on the ground. Also, B is for wheel brakes, so usually its a good idea to hold that down until you get your engine reving.
3) The minimap (M) is useful. As is time accelaration trying to get to your objective.
4) These planes aren't like the ones you've flown in space sims or newer fighter jet combat sims. THEY DO NOT TURN ON A DIME. If you turn too hard, you will spiral, stall, and blow up. Better to dive from above, strafe by the enemy, keep going and climb up for another pass rather than trying to do circles (depends on plane though). You're not going to do quick turns early on (if ever, I have no idea yet), turning too steeply will spiral your plane out of control, and quicker if your flaps aren't set right.
5) Don't try to get behind a bomber and slowly shoot them down. Their tail guns will blow you out of the sky.
6) Aiming is hard. Hitting something is harder. If you're flying with a computer AI, it usually pays off to follow them around, at least until you learn what you're doing.
7) Make sure you raise your landing gear when flying.
8) If you stall, throttle down a bit when falling, it'll usually help to regain control.
EDIT: title was supposed to be newbie tips from newbies

I'm also a newbie learning to fly and I agree with all your points. Though I usually forget to change the flaps position when I take off.

Good idea ilves.
I'm in a similar position and I have some more to add.
Firstly, you need a joystick with a rudder twist control. There are no ifs or buts about it - you need a joystick or this game is unplayable. I bought a Logitech Extreme 3D Pro for about £25 and it's a good stick. It has an analogue throttle control which is also helpful, as well as a large number of buttons and hat switch.
Secondly you need to map the controls to a setup you're comfortable with. I've had a lot of success with the configuration linked to halfway down this post: http://forums.ubi.com/eve/forums/a/tpc/f/23110283/m/9121094645 You can copy-paste the code into your config file so you don't have to change all the mappings manually.
If you can't access that link (ubisoft's forums appear to be down), then here are some basics which should be mapped (assuming you have a full keyboard):
Weapons 1-4: Joystick buttons 1-4
Flaps Up/Down: Joystick buttons 5-6
Landing Gear: G
Arrestor Hook (for carrier landings): H
Throttle: Joystick throttle control
Radiator: R
Time compression + : ]
Time compression - : [
Prop pitch up: Keypad +
Prop pitch down: Keypad -
Supercharger up: Keypad *
Supercharger down: Keypad /
Boost: W
Wheel brakes: B
Dive brakes: D
Change view to no cockpit: Ctrl+F1
Right, once your controls are mapped there are some things you need to know in order to get in the air.
Hint: Choose a forgiving aircraft to begin with, like the SBD Dauntless. If you don't think you can see enough from the cockpit, turn it off with the appropriate command.
Taking off:
1. Taxi to the runway and line yourself up using the rudder. Move the flaps to the TakeOff position. NB: Some planes, such as the Hurricane, don't have multiple flap positions.
2. Smoothly but quickly increase the throttle to max. The torque of the propeller will pull the plane to one side, so counteract the movement gently with the rudder as you begin to pick up speed.
3. Resist temptation to pull up until you hit about 180kmh or 100mph. Once you're in the air, immediately retract the landing gear and enter a shallow climb. Raise the flaps.
Flying:
Just what you can or cannot do while flying depends on the aircraft you're in. Some are more stable than others, while some have very twitchy controls and you'll be in a flat spin before you know it. With this in mind, use gentle movements of the stick to manoeuvre your plane, and cut the throttle and stay calm if you get into trouble. If you lose control the plane will sometimes stabilise by itself, and you can nurse it back into a safe position.
If you run at full throttle for any length of time you will get engine overheating. If this happens, open the radiator and cut back the throttle. Close the radiator during combat as it increases the vulnerability of your engine if it's open.
Landing (the hard part):
1. Fly away from the airfield for a few miles in such as way that you can turn around and have a fairly straight line to the runway.
2. Turn and face the runway. Make sure you won't have to make any massive adjustments as you come in to land.
3. Throttle back to about 35%, wait for your airspeed to drop to 240kmh and move the flaps to the landing position. Lower the landing gear.
4. Use fine adjustment of the throttle to control the speed at which you descend and come in to land. If you feel you're coming in too steeply, cut back the throttle and nose down slightly. Don't let your airspeed fall below around 160kmh or you will find the plane very hard to control and it may just fall out of the sky.
5. As you come over the runway, hopefully around 10m from the ground or less, cut the throttle to zero and pull the nose up, but not too violently - if you still have enough airspeed you'll end up flying up and then downwards rather dramatically.
6. The back will touch down first, then the front. Try not to bounce. Resist the temptation to apply the brakes as you will just nose over and smash the propeller. Roll to a stop.

The funny thing is I found landing on my first try much easier than taking off... did help I knew more buttons at that point. The trick is to just come in as slow as possible and at a shallow angle and not panick if you bounce a little (did that once when I was aiming a little bit in the wrong direction. Turning while landing = bad).